[PATCH] ibm_newemac: Increase number of default rx-/tx-buffers

Eugene Surovegin ebs at ebshome.net
Sat Jan 12 04:48:22 EST 2008


On Sat, Jan 05, 2008 at 01:38:17PM +0100, Stefan Roese wrote:
> On Saturday 05 January 2008, Benjamin Herrenschmidt wrote:
> > On Sat, 2008-01-05 at 10:50 +0100, Stefan Roese wrote:
> > > Performance tests done by AMCC have shown that 256 buffer increase the
> > > performance of the Linux EMAC driver. So let's update the default
> > > values to match this setup.
> > >
> > > Signed-off-by: Stefan Roese <sr at denx.de>
> > > ---
> >
> > Do we have the numbers ? Did they also measure latency ?
> 
> I hoped this question would not come. ;) No, unfortunately I don't have any 
> numbers. Just the recommendation from AMCC to always use 256 buffers.

This cannot be true for all chips. Default numbers I selected weren't 
random. In particular, 256 for Tx doesn't make a lot of sense for 405. 
You just gonna waste memory.

I'd be quite reluctant to follow such advices from AMCC without actual 
details. 

-- 
Eugene




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